Chapter 6 Key Terms: Soil and the Hydrologic Cycle

Vocabulary flashcards for Chapter 6 on Soil and the Hydrologic Cycle.

Hydrologic cycle

The continuous movement of water on, above, and below the surface of the Earth.

Watershed

An area of land that drains to a common point.

Evaporation

The process by which water changes from liquid to vapor.

Transpiration

The process by which water is carried through plants from roots to small pores on the underside of leaves, where it changes to vapor and is released to the atmosphere.

Evapotranspiration

The sum of evaporation and plant transpiration from the Earth’s land and ocean surface to the atmosphere.

Interception

The process by which precipitation is intercepted by vegetation.

Infiltration

The process by which water on the ground surface enters the soil.

Surface runoff

Water that flows over the land surface.

Sediment

Solid material that is moved by water or wind and settles on the surface or at the bottom of a body of water.

Drainage

The removal of excess water from soil.

Capillary water

Water held in the small spaces between soil particles.

Soil storage

The amount of water held in the soil.

Timing of precipitation

The distribution of precipitation over time.

Urban Watershed

A watershed in a city or town.

Soil Properties

Physical, chemical, and biological characteristics of soil.

Potential Evapotranspiration

The maximum amount of evapotranspiration that could occur if there were sufficient water available.

Leaf area index

The ratio of leaf area to ground area.

Fallow

Land left unseeded, normally to recover productivity.

Soil water deficit

The difference between potential evapotranspiration and actual evapotranspiration.

Plastic Mulches

Synthetic films used to cover soil.

Stubble mulch

The practice of leaving crop residue on the soil surface.

Conservation tillage

Soil preparation and planting techniques that minimize disturbance to soil.

Water table

The upper surface of the zone of saturation.

Groundwater

Water held underground in the soil or in pores and crevices in rock.

Vadose zone

The unsaturated zone between the soil surface and the water table.

Aquifers

A body of permeable rock that can contain or transmit groundwater.

Capillary fringe

The zone above the water table where water rises due to capillary action.

Leached

Having had certain constituents washed out of it by percolation.

Preferential flow

The rapid movement of water and solutes through soil macropores, bypassing the soil matrix.

Bypass flow

The rapid movement of water and solutes through soil macropores, bypassing the soil matrix.

Endoaquic

Soil conditions that are saturated with water for extended periods.

Epiaquic

Soil conditions that result from a fluctuating water table at or near the surface.

Perched water table

A localized zone of saturation above a regional water table.

Surface drainage ditches

Open channels used to remove excess water from land.

Land smoothing

Reshaping the land surface to improve drainage.

Effluent

Treated wastewater discharged from a treatment facility.

Drain field

An underground system for disposal of effluent from a septic tank.

Perc Test

A test to determine the water absorption rate of soil.

Water application efficiency

The ratio of water beneficially used to water applied.

Field water efficiency

The ratio of water beneficially used on the field to the water delivered to the field.

Furrows

Small parallel channels used to convey water across a field.

Border irrigation

A method of irrigation where water is applied to the top end of a field and allowed to flow down the slope.

Level basin

A method of irrigation where water is applied to a level area surrounded by dikes.